Water heater with element in the top section - bad?

[TSN79]

I've got a 300 liter water heater that has an electrical element (14 kW). The issue is that the element is positioned in the top third of the heater. I fear the water will become segregated so that only water in the top third will be heated, and the lower section will remain cold. The target temperature is 65°C and the entering water will be around 30°C. What do you think?

 

[russ_watters]

I thought they typically had elements both in the top and bottom section. Do you have the model number?

 

[TSN79]

I thought they typically had elements both in the top and bottom section. Do you have the model number?

I don't have it readily available, but I'm sure the only element is in the top section of the tank.

 

[Averagesupernova]

The water heaters I have dealt with have an upper and lower element. They are 4500 watts each and are never on at the same time. There is an upper and lower thermostat as well. Cold water enters the bottom and hot water is taken off the top. The lower thermostat will naturally be the first to come on. Typically if not a lot of water is used at one time it will be the only one that ever runs. If a lot of hot water is used then the bottom element will not keep up and when the top cools enough it will turn on and it will also switch the bottom one off. Never heard of a water heater with only one element unless it is a small 5 gallon heater.

 

[alphy]

There are a few potential concerns with having an electrical element in the top section of a water heater. One of the main concerns is the potential for stratification, where the hot water rises to the top and the cold water sinks to the bottom. This can result in uneven heating, as the top section may become significantly hotter than the bottom section.

Another concern is the efficiency of heating the water. Since heat rises, the top section of the water heater will heat up faster than the bottom section, potentially leading to wasted energy. This could also result in the water heater taking longer to reach the desired temperature, as the element will need to work harder to heat the colder water in the bottom section.

To address these concerns, it may be beneficial to have a mixing valve installed in the water heater to help prevent stratification. This valve would mix the hot and cold water together, ensuring a more even distribution of temperature throughout the tank.

Additionally, selecting a water heater with a lower wattage element or using a dual element design (with one element in the top and one in the bottom) may also help to mitigate stratification and improve efficiency.

Overall, it is important to consider the placement of the element in a water heater and take steps to prevent potential issues such as stratification. Consulting with a professional plumber or water heater specialist can also provide valuable insight and recommendations for the specific needs of your water heater.